A touch screen display is a device that can detect an object in contact therewith or in proximity thereto. The touch screen display includes a display layer in association with a touch-sensitive matrix that can detect a location of a user's touch by way of a finger or stylus, for example. Touch screen displays are used in various applications such as mobile phones, tablets, and smartwatches. A touch screen display may enable various types of user input, such as touch selection of items or alphanumeric input via a displayed virtual keypad. Touch screen displays can measure various parameters of the user's touch, such as the location, duration, etc.
The display layer may also function in association with pressure-sensitive sensors that can detect the pressure exerted on the touch screen by the user's finger or by the stylus. The pressure-sensitive sensors may include, in a stacked arrangement, a matrix of conductive rows, a resilient dielectric layer, and a matrix of conductive columns. Mutual capacitances at the intersection of each row and column of the matrix may be sensed. These mutual capacitances change in value based on pressure exerted on the touch screen as a result of that pressure compressing the resilient dielectric layer and resultingly changing the distance between the matrix of conductive row and the matrix of conductive columns.
It is desirable for touch screen displays to be as thin as possible so as to save space within a desired device footprint for other components. While the touch screen display described above may provide for touch location sensing as well as touch pressure sensing, the resilient dielectric layer undesirably adds to the thickness in designs where both touch location sensors and touch pressure sensors are used. Accordingly, new designs for compact and thin pressure-sensitive sensors are needed.